Coal mine goaf fire simulation experiment device and method

Abstract

The invention belongs to the technical field of coal mine fire prevention and extinguishing, and particularly provides a coal mine goaf fire simulation experiment device and method. Comprising an experiment table groove body, a working face channel, an air inlet way, an air return way, a ventilation system, a goaf groove body, a water bath heating and heat preservation system, a goaf temperature simulation system, a distributed temperature acquisition system, a goaf gas environment simulation system and a gas acquisition system. According to the invention, the inclination pitching angle, the coal rock porosity, the goaf ignition position, the internal gas components and the like of the goaf can be simulated according to the actual conditions of different working surfaces of each coal mine, and the evolutionary process of the spontaneous ignition accident of the goaf is realized. According to experimental data, development and change states of internal temperature, gas components and the like of the goaf of each coal mine can be determined, key fire prevention and control areas of the goaf in each period of coal mining are found out, early warning is performed in advance, and life and property safety of underground personnel is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mine fire prevention and extinguishing, and in particular provides a coal mine goaf area fire simulation experimental device and method. Background Art

[0002] While coal production has increased significantly with the continued promotion of fully mechanized caving (Jiangsu) technology, this has also resulted in an increase in the amount of residual coal in goafs, significantly increasing the potential risk of spontaneous combustion from oxidation. In addition to causing coal mine fires, spontaneous combustion in goafs can also easily lead to secondary accidents such as gas explosions and coal dust explosions. Spontaneous combustion of residual coal in goafs seriously endangers the lives of underground miners, causes significant economic losses to the country, and hinders the sustainable development of my country's mining enterprises.

[0003] The complex and ever-changing conditions in goafs, along with the inaccessibility of fire sources, create significant uncertainty in mine firefighting efforts, delaying extinguishing efforts and resulting in significant waste of manpower, material, and financial resources, potentially freezing significant coal resources. Therefore, the coal mining industry urgently needs to research how to study the development of fire sources within goafs, the migration of hot spots, and the spread of smoke, as well as how to detect hot spots within goafs and intelligently visualize spontaneous combustion within goafs.

[0004] At present, many researchers have built goaf simulation experimental platforms of different scales by using similar parameters such as geometric similarity, motion similarity, and dynamic similarity to study the gas and temperature in the goaf. However, there are still some defects: 1. Common goaf simulation platforms are relatively small in size, and most experiments conducted are small-scale tests, which are quite different from the actual goaf environment.

[0005] 2. Common goaf simulation experimental platforms only consider the horizontal state, and do not consider the impact of tilt angle and pitch angle on goaf fire experiments.

[0006] 3. Common goaf simulation experimental platforms can only meet the needs of shallow coal seam goaf flow field research. As the mining depth of coal seams increases, the ground temperature rises, and common simulation platforms can no longer meet the experimental requirements. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides a coal mine goaf fire simulation experimental device and method, which is suitable for retreat mining and comprehensive mining working faces. The experimental device includes a test bench trough, a working face channel, an air intake lane, a return air lane, a ventilation system, a goaf trough, a water bath heating and insulation system, a goaf temperature simulation system, a distributed temperature acquisition system, a goaf gas environment simulation system and a gas acquisition system.

[0008] The bottom of the test bench tank is equipped with a retractable hydraulic support for adjusting the inclination and pitch angle of the goaf; The working surface channel is arranged at an opening on one side of the experimental table tank; The middle part of the air intake tunnel is connected to the working face channel; one end is connected to the atmosphere and the other end is connected to the goaf; The middle part of the return air lane is connected to the working face channel; one end is connected to the ventilator and the other end is connected to the goaf; The ventilation system is installed outside the laboratory bench and adopts exhaust ventilation mode. The air inlet is connected to one end of the return air channel. The goaf tank is sleeved and installed inside the test bench tank, with a water bath space between the bottom and the sides of the test bench tank. The bottom of the goaf tank is equipped with fireproof bricks. It is also equipped with multiple replaceable mesh isolation structures to divide the goaf tank into multiple areas for placing coal and rock of different particle sizes. The upper port of the goaf tank is equipped with a cover plate. The water bath heating and insulation system is installed between the goaf tank and the experimental platform tank to heat the goaf tank and simulate the underground temperature environment of the coal mine; The goaf temperature simulation system is set up in the goaf to simulate the heat release from oxidation of residual coal in the high-temperature area of ​​the goaf; The distributed temperature acquisition system is set up in the goaf and has multiple temperature acquisition terminals to measure the temperature changes in different areas of the goaf; The goaf gas environment simulation system has multiple gas release pipelines evenly arranged at the bottom of the goaf, which is used to simulate the release of residual coal oxidation gas, tracer gas release, and gas desorption in the goaf; The gas collection system is connected to one end of the gas pipeline and the other end to the multi-gas monitoring terminal. It is arranged inside the goaf to realize real-time collection and analysis of gas data in the goaf.

[0009] Furthermore, the ventilation system consists of a fan, a variable frequency speed regulating asynchronous motor and is connected to one end of the return air duct in an exhaust ventilation manner. It can adjust the wind speed within the range of 0~10 m / s to meet the air supply requirements of different working surface channels.

[0010] Furthermore, hydraulic supports and support beams are arranged inside the working face channel to simulate the actual working face, so as to ensure the support and stability of the transition area between the fully mechanized caving working face and the tunnel.

[0011] Furthermore, it also includes a water bath heating and insulation system, which consists of a water bath space, a heating tube and a controller. The water bath space is the area between the goaf trough and the experimental table trough, filled with water, and wrapped around the bottom and surrounding areas of the goaf trough; multiple heating tubes are arranged in the water bath space and connected to the control system. The heating rate, temperature range and power of each heating tube can be individually set on the computer side, which can simulate the geothermal environment of the goaf.

[0012] Furthermore, the goaf temperature simulation system consists of heating rods and a computer control terminal. There are 50 heating rods in total, which are evenly arranged inside the goaf. The heating rate, temperature range and power of each heating rod can be individually set on the computer terminal, which can simulate the oxidation and heat release of residual coal in the high-temperature area of ​​the goaf in the form of a point heat source.

[0013] Furthermore, the distributed temperature acquisition system consists of temperature sensors, temperature compensation lines, temperature acquisition instruments and computer terminals. There are 200 temperature sensors in total, which are evenly arranged in the goaf. The height from the bottom plate can be adjusted according to the thickness of the residual coal to measure the temperature changes in the goaf in different areas.

[0014] Furthermore, the goaf gas environment simulation system includes a gas release pipeline, a gas mixing device and a gas flow control device; there are 50 gas release pipelines in total, which are evenly arranged at the bottom of the goaf; the ends of the gas release pipelines in the goaf are wrapped with filter gauze to prevent the gas pipelines from being blocked by coal gangue; the gas flow control device consists of a high-precision flow meter and a touch panel.

[0015] Furthermore, the gas collection system consists of a gas collection head, sponge, gas collection pipeline and multi-gas monitoring terminal; there are 50 gas collection heads in total, which are connected to one end of the gas collection pipeline, filled with sponge, and connected to the multi-gas monitoring terminal at the other end. They are evenly arranged inside the goaf to realize real-time collection and analysis of gas data in the goaf.

[0016] The present invention also provides a coal mine goaf fire simulation experimental method, comprising the following steps: Step 1: Check the platform ventilation system, water bath heating and insulation system, goaf temperature simulation system, distributed temperature acquisition system, goaf gas environment simulation system, gas acquisition system, etc. to ensure that all parts used in the experiment are working properly; Step 2: Select an appropriate scale based on the actual working surface size; Step 3: Adjust the height of the hydraulic support at the bottom of the platform according to the actual tilt and pitch angle of the goaf to ensure that the tilt and pitch angle of the platform are consistent with the actual site; Step 4: After the platform angle is determined, use a gantry crane to lift the goaf cover; Step 5: Based on the coal and rock caving situation in the goaf to be studied, the height and other parameters are reduced according to the selected scale to calculate the filling height of coal and rock in each mesh isolation area of ​​the test bench; Step 6: Based on the porosity and permeability distribution characteristics of the coal rock in the goaf, select coal rock particles with similar particle sizes to fill the platform goaf; Step 7: After the coal and rock filling in the goaf is completed, use the gantry crane to reinstall the goaf cover lifted in step 4 to the top of the goaf; Step 8: Use glass glue to seal the joints between the cover plates and the joints between the cover plates and the edge of the goaf; Step 9: During the experiment, adjust the water bath heating and insulation system according to the actual ground temperature in the goaf; Step 10: Start the ventilation system, ventilate the goaf, and check the air tightness of the platform. If there is no leakage, the experimental device is well sealed. If there is leakage, continue to use glass glue to reseal the leakage point; Step 11: After confirming that the experimental platform is sealed properly, start the distributed temperature acquisition system and gas acquisition system; Step 12: During the experiment, according to the oxidation and heating gas release and gas desorption laws of the experimental coal sample, the parameters of the goaf gas environment simulation system are adjusted, the goaf gas environment simulation system is started, and the dynamic gas concentration distribution is evolved; Step 13: During the experiment, turning off the goaf temperature simulation system allows for research on the migration patterns of high-temperature points in the goaf's residual coal oxidation process. Turning on the goaf temperature simulation system allows for simulation of goaf fire accidents, the evolution of toxic gas migration, and fire development.

[0017] This method simulates goaf ground temperature, pitch angle, coal rock porosity, goaf ignition location, and residual coal gas analysis patterns based on the actual conditions of each coal mine's working face, thereby demonstrating the evolution of spontaneous combustion accidents in coal mine goafs. Based on this experimental data, each coal mine can clearly identify the development and changes in goaf internal temperature and gas composition, identify key areas for goaf fire prevention and control during each coal mining period, and provide early warnings to protect the lives and property of underground personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are incorporated in and constitute a part of this application and are used to provide a further understanding of the present invention.

[0019] Figure 1 This is the front view of the experimental table; Figure 2 This is the side view of the experimental bench; Figure 3 This is a top view of the experimental bench; Figure 4It is a mesh isolation structure inside the goaf of the experimental platform; Figure 5 This is the layout of each pipeline on the experimental bench.

[0020] Among them: 1-laboratory table tank; 2-retractable hydraulic support; 3-working face channel; 4-working face support; 5-inlet air lane; 6-return air lane; 7-ventilator; 8-variable frequency speed regulation three-phase asynchronous motor; 9-goaf tank; 10-fireproof brick; 11-mesh isolation structure; 12-cover plate; 13-water bath space; 14-heating tube; 15-computer; 16-hollow tube; 17-heating rod; 18-temperature sensor; 19-temperature compensation line; 20-temperature acquisition Instrument; 21-gas release pipeline; 22-filter gauze; 23-gas mixing device; 24-touch panel; 25-high-precision flow meter; 26-N2 gas cylinder; 27-CO gas cylinder; 28-CO2 gas cylinder; 29-O2 gas cylinder; 30-C2H2 gas cylinder; 31-C2H4 gas cylinder; 32-C2H6 gas cylinder; 33-SF6 gas cylinder; 34-CH4 gas cylinder; 35-gas sampling head; 36-cotton; 37-gas sampling pipe; 38-multi-gas monitoring terminal. DETAILED DESCRIPTION

[0021] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0022] refer to Figure 1-3 This paper uses a fully mechanized retreating coal face as a prototype and, based on similarity theory, constructs a coal mine goaf fire simulation experimental device. The device model's geometric scale can be customized according to experimental needs. This provides experimental conditions for the development of spontaneous combustion of coal in goafs and confined areas, the migration of harmful gases, disaster simulation and reproduction, and the monitoring of high-temperature spots.

[0023] The present invention provides a coal mine goaf fire simulation experimental device, which is suitable for retreat-type fully-mechanized mining working faces, including a test bench tank body 1, a working face channel 3, an air intake tunnel 5, a return air tunnel 6, a ventilation system, a goaf tank body 9, a water bath heating and insulation system, a goaf temperature simulation system, a distributed temperature acquisition system, a goaf gas environment simulation system and a gas acquisition system; wherein, The experimental table tank body 1 has a retractable hydraulic support 2 at the bottom, which can adjust the inclination and pitch angle of the goaf according to the actual inclination and pitch angle of the working surface; The working face channel 3 is set at the side opening of the experimental table trough 1; the three-dimensional design dimensions of the working face channel 3 are 5×0.2×0.2 m, and the working face support 4 is arranged inside it to simulate the hydraulic support and support beams in the actual working face, so as to ensure the support and stability of the transition between the fully mechanized caving working face and the tunnel.

[0024] The middle of the air intake tunnel 5 is connected to the working face channel 3; one end of the tunnel is connected to the atmosphere, and the other end is connected to the goaf. In this solution, the goaf is the area where coal and rock are loaded; The return air lane 6 is connected to the working face channel 3 in the middle; one end is connected to the ventilator 7, and the other end is connected to the air in the goaf; The ventilation system consists of a fan 7 and a variable-frequency, three-phase asynchronous motor 8. The platform utilizes exhaust ventilation, connected to the return air duct 6. This allows for wind speed adjustment within a range of 0 to 10 m / s to meet the air supply requirements of different work surfaces. The three-dimensional design dimensions of the inlet and return air ducts 5 and 6 are 1.7 x 0.2 x 0.2 m.

[0025] The goaf trough body 9 is sleeved inside the experimental table trough body 1, and there is a water bath space 13 between the bottom and the four sides of the experimental table trough body 1. The three-dimensional size of the goaf trough body 9 is designed to be 5×10×1.2 m, and the lower 0.2 m will be used to arrange fire bricks 10, so its actual experimental three-dimensional size is 5×10×1 m.

[0026] The mesh isolation structure 11 used to fill the coal and rock areas inside the goaf has a three-dimensional size of 1×0.2×1m, a total of 250, and the mesh size is set to 1 cm. Figure 4 The mesh isolation structure 11 can reduce the difficulty of replacing experimental materials.

[0027] The particle size of coal and rock inside the goaf is determined based on the empirical formula for porosity distribution and permeability distribution in the goaf. The specific contents are as follows: The midpoint of the actual working face top line is taken as the coordinate origin, the direction to the deep part of the goaf is the positive direction of the x-axis, and the direction along the working face to the return air channel is the positive direction of the y-axis. Therefore, the porosity distribution of the goaf can be calculated using the following formula:

[0028] Where: —porosity of the goaf, dimensionless; —Porosity along the working surface, i.e., the x-direction, dimensionless; —Porosity along the depth direction of the working surface, i.e., the y-direction, dimensionless; L—working surface length, m; —The strike distance from a point in the goaf to the working face, m, with a value range of [0, D]; —The coordinate value of a point in the goaf in the y-axis direction, m, with a value range of [-L / 2, L / 2].

[0029] The permeability of porous media depends on the porosity. When the porosity size and distribution of the porous media are constant, the permeability is only related to the porosity of the porous media. The relationship equation between the permeability and porosity of the porous media in the goaf is: (4) Where: is the permeability, m 2 ; is the air dynamic viscosity coefficient, at room temperature =1.834×10 -5 Pa·s; is the porosity of the goaf, dimensionless.

[0030] After the actual porosity and permeability of the goaf are calculated, they are proportionally reduced according to the selected geometric scale to determine the coal and rock particle sizes in each part of the mesh isolation structure 11.

[0031] The goaf cover 12 is used to seal the experimental platform and consists of 50 small covers with a size of 1×1×0.2 m, which is easy to disassemble and install.

[0032] The water bath heating and insulation system is arranged between the goaf trough 9 and the experimental bench trough 1 to simulate the geothermal environment of the goaf; the water bath heating and insulation system specifically includes a water bath space 13, a heating tube 14 and a controller 15. The water bath space 13 is the area between the goaf trough 9 and the experimental bench trough 1, filled with water, and wrapped around the bottom and surrounding areas of the goaf trough 9; multiple heating tubes 14 are arranged in the water bath space 13 and connected to the control system 15. Each heating tube 14 can be individually set with a heating rate, temperature range and power on the computer terminal 15, which can simulate the real geothermal environment of the goaf.

[0033] The three-dimensional dimensions of the water bath space 13 are designed to be 10.4×5.4×1.4 m, covering the surrounding and bottom areas of the goaf trough 9, with a distance of 0.2 m between the two.

[0034] The goaf temperature simulation system includes heating rods 17 and a computer control terminal 15. The heating rods 17 are cylindrical nickel-chromium alloy electric heating rods with a diameter of 0.1m and a length of 0.3m. There are 50 of them, which are evenly arranged inside the goaf. The heating rate, temperature range and power of each heating rod 17 can be individually set on the computer terminal 15, which can simulate the oxidation and heat release of residual coal in the high-temperature area of ​​the goaf.

[0035] The distributed temperature acquisition system is set up in the goaf and has multiple temperature acquisition terminals for measuring the temperature changes in the goaf in different areas. It specifically includes a temperature sensor 18, a temperature compensation line 19, a temperature acquisition instrument 20 and a computer terminal 15. Among them, the temperature sensor 18 uses a high-temperature resistant armored thermocouple. A total of 200 temperature acquisition points are arranged in the goaf to measure the temperature changes in the goaf in different areas.

[0036] The goaf gas environment simulation system includes a gas release pipeline 21 and a gas flow control device; there are 50 gas release pipelines 21, which are evenly arranged at the bottom of the goaf and are used to simulate the release of oxidation gas, tracer gas release, and gas desorption from the goaf; the end of the gas release pipeline 21 in the goaf is wrapped with a filter mesh 22 to prevent the gas pipeline from being blocked by coal gangue; the gas flow control device consists of a high-precision flow meter 25, a touch panel 24, and a gas mixing device 23, which can achieve precise control of the release rates of nine types of gases, including N2, CO, CO2, O2, C2H2, C2H4, C2H6, SF6, and CH4. The touch panel in this solution is an operating interface, which is actually a controller. The controller controls the input of the corresponding gas according to the flow meter data.

[0037] The gas collection system consists of a gas sampling head 35, a sponge 36, a gas sampling pipeline 37, and a multi-gas monitoring terminal 38. There are 50 gas sampling heads 35, which are connected to one end of the gas sampling pipeline 37 and filled with sponge 36. The other end is connected to the multi-gas monitoring terminal 38. They are evenly arranged inside the goaf to realize real-time collection and analysis of gas data in the goaf. Figure 5 , which shows the layout of each pipeline of the experimental platform.

[0038] The entire test bench tank 1 is welded from 4 mm thick white steel plates. All parts are treated for corrosion and feature a sealed internal insulation layer to ensure high-temperature resistance above 1000°C. Each experimental pipeline is connected to the platform through a hollow tube 16 at the bottom of the test bench, penetrating a 0.2 m water bath and 0.2 m fireproof bricks, ensuring that the collection side of each pipeline is located within the goaf.

[0039] The present invention also provides an experimental method for a coal mine goaf fire simulation experimental device, comprising the following steps: Step 1: Check the platform ventilation system, water bath heating and insulation system, goaf temperature simulation system, distributed temperature acquisition system, goaf gas environment simulation system, gas acquisition system, etc. to ensure that all parts used in the experiment are working properly; Step 2: According to the actual working face inclination length, determine the appropriate scale for similar experiments to select the working face 3 inclination length of the coal mine goaf fire simulation experimental device: the actual working face inclination length; Step 3: According to the actual goaf tilt and pitch angle, adjust the height of the hydraulic support 2 at the bottom of the platform to ensure that the platform tilt and pitch angle is consistent with the actual site; Step 4: After the platform angle is determined, a gantry crane is used to lift the goaf cover 12 away; Step 5: Based on the coal and rock caving situation of the goaf to be studied, the height of the coal and rock filling in each part of the mesh isolation structure 11 in the test bench is calculated after reducing its height according to the selected scale; Step 6: Based on the porosity and permeability distribution characteristics of the coal rock in the goaf, select coal rock particles with appropriate particle size that meet similar criteria to fill the interior of the platform goaf; Step 7: After the coal and rock filling in the goaf is completed, the goaf cover plate 12 lifted off in step 4 is reinstalled on the top of the goaf using a gantry crane; Step 8: Use glass glue to seal the joints between the cover plates 12 and the cover plates 12, and the joints between the cover plates 12 and the edge of the goaf; Step 9: During the experiment, adjust the water bath heating and insulation system according to the actual ground temperature in the goaf; Step 10: Start the ventilation system, ventilate the goaf, and check the sealing of the platform. If there is no leakage, the sealing of the experimental device is intact. If there is leakage, continue to use glass glue to reseal the leakage point; Step 11: After confirming that the experimental platform is sealed properly, start the distributed temperature acquisition system and gas acquisition system; Step 12: During the experiment, according to the oxidation and heating gas release and gas desorption laws of the experimental coal sample, the parameters of the goaf gas environment simulation system are adjusted, the goaf gas environment simulation system is started, and the dynamic gas concentration distribution is evolved; Step 13: During the experiment, turn off the goaf temperature simulation system to study the migration law of high-temperature points of oxidized coal in the goaf; turn on the goaf temperature simulation system to simulate goaf fire accidents, evolve the migration of toxic gases and the development of fire.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A coal mine goaf fire simulation experimental device, characterized in that: It includes the experimental table tank, working face channel, air inlet tunnel, return air tunnel, ventilation system, goaf tank, water bath heating and insulation system, goaf temperature simulation system, distributed temperature acquisition system, goaf gas environment simulation system and gas acquisition system; among them, The experimental table tank has a retractable hydraulic support at the bottom; The working surface channel is arranged at an opening on one side of the experimental table tank; The middle part of the air intake tunnel is connected to the working face channel; one end is connected to the atmosphere and the other end is connected to the goaf; The middle part of the return air lane is connected to the working face channel; one end is connected to the ventilator and the other end is connected to the goaf; The ventilation system is installed outside the test bench, including a ventilator and a three-phase asynchronous motor with variable frequency speed regulation. It adopts an exhaust ventilation method. The air flows from the air inlet channel through the working face channel and flows into the ventilator from the return air channel. The goaf trough is sleeved and installed inside the experimental table trough. The gaps between the bottom and the sides of the experimental table trough are water bath spaces. Fireproof bricks are installed at the bottom of the goaf trough. There are also multiple replaceable mesh isolation structures to divide the goaf trough into multiple areas for placing coal and rock of different particle sizes. A cover is installed on the upper port of the goaf trough. The water bath heating and insulation system is installed between the goaf tank and the experimental platform tank to heat the goaf tank and simulate the ground temperature environment of the goaf; The goaf temperature simulation system is set up in the goaf to simulate the heat release from oxidation of residual coal in the high-temperature area of ​​the goaf; The distributed temperature acquisition system is set up in the goaf and has multiple temperature acquisition terminals to measure the temperature changes in different areas of the goaf; The goaf gas environment simulation system has multiple gas release pipelines evenly arranged at the bottom of the goaf to simulate the release of residual coal oxidation gas, tracer gas release, and gas desorption in the goaf; The gas collection system is connected to one end of the gas pipeline and the other end to the multi-gas monitoring terminal. It is arranged inside the goaf to realize real-time collection and analysis of gas data in the goaf.

2. A coal mine goaf fire simulation experimental device and method according to claim 1, characterized in that: Hydraulic supports and support beams are arranged inside the working face channel to simulate the actual working face.

3. A coal mine goaf fire simulation experimental device and method according to claim 1, characterized in that: The water bath heating and insulation system includes a water bath space, heating tubes and a controller. The water bath space is the area between the goaf trough and the experimental table trough, filled with water, and wrapped around the bottom and surrounding areas of the goaf trough; multiple heating tubes are arranged in the water bath space and connected to the controller. The heating rate, temperature range and power of each heating tube can be individually set on the computer side, which can simulate the geothermal environment of the coal seam where the working face is located.

4. A coal mine goaf fire simulation experimental device and method according to claim 1, characterized in that: The goaf temperature simulation system includes multiple heating rods and a computer control terminal. The heating rods are evenly arranged inside the goaf. The heating rate, temperature range and power of each heating rod can be individually set on the computer terminal, which can simulate the oxidation heat release of residual coal in the goaf in the form of a point heat source.

5. A coal mine goaf fire simulation experimental device and method according to claim 1, characterized in that: The distributed temperature acquisition system includes a temperature sensor, a temperature compensation line, a temperature acquisition instrument and a computer control terminal. The temperature sensor uses a high-temperature resistant armored thermocouple. Multiple temperature acquisition points are arranged in the goaf. The height of the temperature acquisition point from the bottom plate can be adjusted according to the thickness of the residual coal to measure the temperature changes of the goaf in different areas; the temperature sensor is buried in the goaf and connected to the temperature acquisition instrument through the temperature compensation line. The temperature acquisition instrument is connected to the computer through a network cable or optical fiber.

6. A coal mine goaf fire simulation experimental device and method according to claim 1, characterized in that: The goaf gas environment simulation system includes multiple gas release pipelines, gas mixing devices and gas flow control devices; the gas release pipelines are evenly arranged at the bottom of the goaf; the ends of the gas release pipelines in the goaf are wrapped with filter gauze; the gas flow control device consists of a high-precision flow meter and a touch panel.

7. A coal mine goaf fire simulation experimental device and method according to claim 1, characterized in that: The gas collection system includes multiple gas collection heads, gas collection pipelines and multi-gas monitoring terminals; the gas collection head is connected to one end of the gas collection pipeline and filled with sponge, and the other end is connected to the multi-gas monitoring terminal, which is evenly arranged inside the goaf.

8. A coal mine goaf fire simulation experimental method, characterized by: According to the simulated actual working face inclination length of goaf, the similarity experiment scale is determined as the working face inclination length of coal mine goaf fire simulation experimental device: actual working face inclination length; Adjust the tilt and pitch of the hydraulic support at the bottom of the platform according to the actual tilt and pitch angle of the goaf; According to the coal and rock caving situation of the goaf to be studied, the height of the coal and rock in the mesh isolation structure of each part of the goaf in the experimental platform is calculated after reducing its height according to the selected scale; According to the porosity and permeability distribution characteristics of coal rock in the goaf, coal rock particles with appropriate particle size that meet similar criteria are selected to fill the platform goaf; After the coal and rock filling in the goaf is completed, the goaf cover is installed and sealed; After sealing, set the water bath heating and insulation system according to the actual ground temperature of the goaf; Start the ventilation system, ventilate the goaf, and check the sealing condition of the experimental platform; After confirming that the experimental platform is sealed properly, start the distributed temperature collection system and gas collection system; During the experiment, according to the oxidation and heating gas release and gas desorption laws of the experimental coal samples, the parameters of the goaf gas environment simulation system were adjusted, the goaf gas environment simulation system was started, and the dynamic gas concentration distribution was evolved; During the experiment, turning off the goaf temperature simulation system can be used to study the migration law of high-temperature points of oxidized coal in the goaf; turning on the goaf temperature simulation system can be used to simulate goaf fire accidents, evolve the migration of toxic gases and the development of fire.

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